Forward vs Reverse Reaction (both endo/exo thermic)

[ldv1452]

Can both the forward and reverse reaction be endothermic or exothermic? Or must they ALWAYS be inverse one another?

Thanks

 

[Borek]

What about energy conservation?

 

[horsecandy911]

They cannot both be exothermic or endothermic. Enthalpy (H) is a state function. This means that the enthalpy of a system is completely independent of how one arrived at that system. It's like mass. It follows from this that the enthalpy change in any process is expressed by:

$$H_{final}-H_{initial} = \Delta\ H$$

for all processes. So if the forward process has a negative change in enthalpy (exothermic), the reverse process will have a positive change in enthalpy of equal magnitude. For a reverse reaction, you just switch the "final" and "initial" states, which amounts to multiplying the left by negative one. So this equation relates forward and reverse processes:

$$H_{for}= -H_{rev}$$

EDIT:
Sorry I can't get LaTex to work right, I'm new to this.

 

[ldv1452]

They cannot both be exothermic or endothermic. Enthalpy (H) is a state function. This means that the enthalpy of a system is completely independent of how one arrived at that system. It's like mass. It follows from this that the enthalpy change in any process is expressed by:

$$H_{final}-H_{initial} = \Delta\ H$$

for all processes. So if the forward process has a negative change in enthalpy (exothermic), the reverse process will have a positive change in enthalpy of equal magnitude. For a reverse reaction, you just switch the "final" and "initial" states, which amounts to multiplying the left by negative one. So this equation relates forward and reverse processes:

$$H_{for}= -H_{rev}$$

Good answer on this. I appreciate it. Thanks!

 

[LudusRex]

for your question! The forward and reverse reactions can both be endothermic or exothermic, or they can be inverse of each other. It really depends on the specific chemical reaction and the conditions under which it is occurring. In some cases, the forward reaction may be endothermic while the reverse reaction is exothermic, or vice versa. In other cases, both reactions may be endothermic or both may be exothermic.

It is important to note that the direction of a reaction is not determined by its thermodynamic properties (such as endothermic or exothermic), but rather by the relative concentrations of reactants and products. This is described by Le Chatelier's principle, which states that a system at equilibrium will shift in a direction that counteracts any changes made to it.

In summary, the forward and reverse reactions can have varying thermodynamic properties, but the direction of the reaction is determined by the concentrations of reactants and products. So, it is possible for both reactions to be endothermic or exothermic, but they do not necessarily have to be inverse of each other.